Lean overloaded names from two `open`s: term mode resolves them, rw doesn't

Tested on Mathlib v4.35.0. Under open Finset SimpleGraph, disjoint_left.2 h : Disjoint s t (Finsets) elaborates, because the expected type picks Finset.disjoint_left. But rw [disjoint_left] errors with 'Ambiguous term ... SimpleGraph.disjoint_left / Finset.disjoint_left', since a rewrite rule has no expected type. Worse, with only open SimpleGraph, rw [disjoint_left] silently uses the graph lemma and fails with 'did not find Disjoint ?m ?m'. Same pattern with exp: under open Real alone, continuous_exp.comp ... against a Continuous fun x => cexp ... goal fails with 'Type mismatch ... Continuous (rexp ∘ ?m)'. Under open Real Complex it resolves to Complex.continuous_exp. Rule of thumb: always fully qualify names inside rw/simp lists when more than one namespace is open, and suspect a single-namespace shadow when a rewrite 'did not find' a pattern that is clearly there.